Nanoscale Characterization of Chemical and Structural Properties of the Au/(100) β-Ga₂O₃ Interface

Au/β-Ga2O3 Schottky contacts deposited at room temperature via electron-beam evaporation are characterized electrically with current density–voltage (J–V) and capacitance–voltage (C–V) measurements. The ideality factor and Schottky barrier heights measured from J–V and C–V are determined to be 1.32, 1.37 eV, and 1.98 eV, respectively. Due to the peculiarities of the electrical properties of the Au/β-Ga2O3 Schottky contacts, scanning transmission electron microscopy (STEM) was performed. High-angle annular dark-field (HAADF)-STEM imaging reveals an inhomogeneous chemical reaction occurred at the metal–semiconductor interface. The reaction is signified by void formation 5–20 nm below the interface, Ga diffusion into Au at the interface, and Ga interstitial diffusion toward the interface. Energy-dispersive X-ray spectroscopy (EDS) mapping shows Ga diffusion into the Au contact region accompanied by a transitional region of 4–5 nm.